jiayuasu commented on code in PR #614: URL: https://github.com/apache/incubator-sedona/pull/614#discussion_r855815163
########## sql/src/main/scala/org/apache/spark/sql/sedona_sql/expressions/raster/Functions.scala: ########## @@ -771,3 +771,45 @@ case class RS_Normalize(inputExpressions: Seq[Expression]) } +/// Append the Normalized Difference between two bands to the image array data as a new band Review Comment: OK. I was wrong. Then there is an RS operator which is missing: RS_AppendBand, otherwise the user won't be able to re-generate GeoTiffs after manipulating individual bands using [Raster operators](https://sedona.apache.org/api/sql/Raster-operators/). 1. RS_AppendBand takes at least 2 parameters: data, new_band, nBands. The new_band will be appended to the end of data. nBands is the num of bands in data, before appending. nBands might come in handy if you need to expand the data array. With this more generic RS_AppendBand func, RS_AppendNormalizedDifference is no longer needed since we already has RS_NormalizedDifference func. 2. On a side note, since the RS operator unit is a single band, it seems to me that all "Band" postfix in the RS operators' names are redundant and will produce super long SQL queries. What do you think? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
